Free Tool
System Size Calculator
Estimate the solar array size you need to cover your annual usage, with adjustment for peak sun hours and how much you expect to offset versus export.
Find this on your bill — 12 month total.
How much of your generation you expect to export (you can’t use every kWh at peak). 20–40% is typical without a battery.
Recommended array
Array size
5 kW
peak (kWp)
Est. annual output
8.2 MWh
kWh / year
Daily usage
16.4 kWh
kWh / day
Panels (est.)
~12
at 430W panels
This is a planning estimate, not a design. Roof orientation, shading and real sun hours change the answer — an installer provides the final layout.